(For this material realm which is a tree) In the manushya lOka (earth), which is below, the roots, i.e., the bondage of karma (deeds) are spread.

Rendering based on ALkoNdavilli gOvindhAchArya swAmy’s English translation of gIthA bhAshyam

‘Below, in the world of men, do stretch its karma-bound rootlets.’

This Tree having the root in Brahma-loka, and the (branch-)ends in (the world of) man, has its rootlets again in this world of man. And these rootlets are karma-bound,i.e., karmas are their causes, and they make these rootlets in this world of man. For, works (karma) wrought when in the state of man, are the roots from which, on the one hand, the conditions of man, animals etc., result on lower levels, and the conditions of devas etc., on higher levels above.